High-pressure centrifugal pump



July 3, 1928.

M. SPILLMANN ET AL HIGH PRESSURE CENTRIFUGAL PUMP I ENTORS ATTORNEY July 3, 1928. 1,675,830

M. SPILLMANN ET AL HIGH PRESSURE CENTRIFUGAL PUMP Filed April 7, 1926 4Sheets-Sheet 2 0./1f DORER.

IN on ATTORNEY July 3, 1928. 1,675,830

M. SPILLMANN ET AL HIGH PRESSURE CENTRIFUGAL PUMP Filed April 7, 1926 -4 Sheets-Sheet 3 ATTORN EY July 3, 1928.

M- SPlLL-MANN ET AL HIGH PRESSURE CENTRIFUGAL PUMP Fild Aprii v, 1926 4 Shets-Sheet 4 e\\ N N A .c m t i EJIL h 351... 1

w SW 0. h. DORER.

IN TORS.

ATTOR N EY Patented July 3, 1928.

UNITED STATES PATENT OFFICE.

MAX SPILLMANN, OF RICH FIELD, AND OSCAR H. DORER, OF EAST ORANGE, NEW JER- SEY, ASSIGNORS T0 WORTHINGTON PUMP AND MACHINERY CORPORATION, 01 NEW YORK, N. Y., A. CORPORATION OF VIRGINIA.

nrerr-rnnssunn CENTRIFUGAL PUMP.

Application filed Apr-117, 1926. Serial No. 100,205.

This invention relates to centrifugal pumps and more particularly to high pressure boiler feed pumps.

The present and growing practice in the design and construction of power plants is to feed the water to the boilers under high pressure and at relatively high temperatures, such pumps operating at very high discharge pressures. In the construction of high pressure feed pumps'of this type it is diflicult to provide casings of sufficient strength to handle or withstand the stresses due to the pressure within the pump and particularly in pumps which have the casing constructed or split so as to permit access to the interior parts of the pump, such as diffusion rings, impellers, etc., for purpose of replacement or repair.

It is an object of the present invention to provide a pump capable of handling high pressures which embodies in substance an inner and outer casing with pressure fluid between them. giving in effect a two-stage distribution of the stresses. These casings are arranged to provide in substance :1 space or chamber between their facing'surfaces which preferably has communication with the suction end or an intermediate stage of the pump to permit the fluid pumped to enter the chamber under suitable pressure, the said fluid cooperatingwith the casings in absorbing the stresses due to the high pressures under which the fluidis pumped.

A further object of the invention is to provide ,in a pump as specified, diffusion rings which are connected one to the other" with suitable fittings and wherein the individual stage pressures acting on the diffusers hold the rings tight against leakage without the use of bolts or analogous fastening devices.

With these objects in view, the invention consists in various features of construction and combination of parts, whichdvwill be first described in connection with the accompanying drawings, showing a high pressure.

centrifugal pump of the preferred form embodying the invention, and the features forming the invention will be specifically pointed out in the claims.

In the drawings- Figure 4 is a vertical section through the pump taken on the line 4 4 of Figure 1.

Figure 5 is a view partly in section and partly in elevation of one of the diffusion rings.

Figure 6 is a view partly in side elevation and partly in section of a modified form of the invention.

Referring more particularly to the drawings, the improved high pressure centrifugal pump comprisesthe outer casing l which is formed of the upper section 2 and the lower section 3. The sections 2 and 3 are provided with engaging flanges 4 and the upper section- 2 has a plurality of. bosses 5 thereon, through which bolts 6 extend for detachably connecting the sections 2 and 3 to permit removal of the section 2 for-access to the interior of the pump and still provide suflicient strength of-connection to maintain the sec tions tightly connected under stresses due to the relatively hi h pressures to which the pump is subjected.

In pumps designed for use in connection with extremely high pressures of fluid pumped, it is practically impossible to provide a split casing of suflicient strength to withstand the pressures and hold the sec.- tions of the caslngs together with bolts and in the present invention a second or inner casing is formed by the diffusion rings 8. The diffusion rings 8 are constructed in such manner as to form the inner casing as well as to form the diffuser and return channel. The rims 7 of the diffusion rings are shown, in Figure 1 of the drawings as having edge engagement with the webs 9 of the diffusion ring next thereto and aside from such engagement the diffusion rings are free from connection with each other. The unbalanced or thrust pressure of the diffusion rings 8 is that due to stage ressure and exposed surface and each diffusion ring carries the thrust from the next succeeding ring. These high pressures serve to hold the joints between the successive rings tight, and the use or need of bolts or other analogous attaching devices for connecting the rings is eliminated. Each of the rings 8 has an annular rib 10 on its perimeter which engage in grooves 11in the casing sections 2 and 3. By particular reference .to Figure 1 on the drawings, it will be noted, however, that the grooves 11 are wider than the ribs 10 so as to permit the eflfective sealing between leakage that may occur simply passes to the chamber and does no harm.

For sealing the last difi'usion ring indicated at 8 in Figure 1 of the drawings a lead bull ring 12 is provided which fits over the cone 13 on the diffusion ring 8. The bull ring 12 fits against the shoulder 14 on the casing 1 and the pressure in the-pump forces the ring 12 tightly on the cone joint 13 and. gives the eflect of two casings in one. The last pressure stage is shown at 36 without difl'usion ring so as to give the discharge chamber a small radial dimension and aid in reducing casing stresses.

The diffusion rings'8'and the casing sections 2 and 3 are constructed to provide a series of clearance spaces 15 bctween the perimeters of the diffusion rings and the inher surfaces of the casing sections 2 and 3.

. the drawings to permit the fluid to be pumped to enter the chamber 15 under suction pressure. The fluid under suction pressure acts in conjunction with the inner casing formed by the diffusion rings 8 and the outer casing 1 to withstand the stresses and pressure of the fluid pumped and to distribute the pressure in such manner as to subject the outer casing 1 to a pressure so much lower than the pump pressure as to permit the casing to be made in sections 2 and 3, joined by the bolts 6 even with the highest discharge pressure. With the stresses on the outer casing distributed by proper pressure in the chamber 15 the outer casing 1 may be comparatively light and if desired, may be strengthened to support the discharge pressure and the thrust against the suction head by longitudinal and peripheral ribs as shown at 37 and 38. V

In pump structures where the suction pressure is not suflicient to secure the desired pressure in chamber 15 or a desired amount of pressure from other source is not available, any one of the other diflusion rings 8 such as the third-stage difl'usion ring 8 may be provided with openings 17 c as shown sure within the chamber 15-and in such instances the first or initial difiusion ring is free from openings having communication with the chamber 15 or the channel 16. In

all other respects the modified form of pump illustrated in Figure 6 is identical with the preferred type of pump illustrated in the other figures of the drawings. the successive rings by the action of the pressure thereon. Any

The impellers 20 are mounted upon the shaft 21 which shaft is rotatable in suitable bearings 22 and in the present form of the invention hydraulic balancing of the impeller thrust is provided. The hydraulic alancin of the impeller thrust is accomplished t rough the balancing disc 23 and in case the shaft 21 and impellers 20 move longitudinally the disc 23 will be forced away rom engagement with the casing-carried disc 24 and the fluid will leak through the sleeve 25 and through the space formed between the discs 23 and 24 into the chamber 26 from which it will be returnedgthrough the piping 27 into the chamber 15. The back pressure through the piping 27 may be controlled by suitable choke (not shown) of any approved construction in the pipin 27. The hydraulic balancing of centrifuga pump is well known and in the present a plication differs from previous structures in that the back pressure fluid flows into the chamber 15. A ball thrust bearing 28 of approved construction is rovided at the end of the shaft 21 and is esigned so as to run free under ordinary circumstances; however, when the engaging surfaces of the discs 23 and 24 wear to such an extent as to decrease their efliciency the thrust bearing 28 will be brought into effective operation.

In the-operation of the improved centrifugal pump the fluid to be pumped enters through the intake or suction 30 and passes through the successive stages of the pump identified by the various difl'usion rin s 8 and the impellers 20, the path and directional flow of the fluid being regulated and the pressure increased from stage to stage through the specific construction of the diffusion rings, the vanes on the diflusion'rings as shown at 32 and the impellers. The discharge is through the o ening 33.

From the foregoing escription taken in connection with the accompanying drawings it will be apparent that a pump has been provided in'which the outer casing, with the exception of the portion surrounding the last stage, is subjected only to suction ressure or such pressure depending upon t e-stage which is tapped to provide the balancing fluid in the chamber 15, and which construction, therefore, gives variable stresses on the inner casing depending on the particular stage and is maximum at next to the last stage only, which stage, being of small-exfor pumping feed water in such instances;

in that ina pump embodying a casing having irregular surfaces, the expansion and contraction due to'the variances in temperature and particularly to the heatcaused by the hot water flowing through the pump, cause cracking and distortion which, in turn, affects the efliciency of the pump and in the present invention, the use of the diffusion rings 8 as the inner casing, enables the outer casing to be of symmetrical construction and -.eliminates irregular surfaces and consequently reduces liability of cracking or distortion of the outer casing under heat action.

It. will be understood that the invention is not to be limited to the specific construction or arrangement of arts shown but that thesd may be modified widely within the invention defined by the claims.

IVhat is claimed is:

1. In a centrifugal pump, an outer casing and series of diffusionri'ng's within the outer casing disposed in-engagement one with the one next thereto and constructed and providing exposed surfaces whereby the stage pressure in the pump causing thrust pressure on the difiusion rings will maintain the rings in tight engagement. with each other, and means engaging the last diffusion ring in the series and engaging said outer casing for joining, in effect, said rings and outer casing in a "unit, said outer casing and diffusion rings having a chamber between their facing surfaces, said chamber having communication with the interior of the diffusion rings at a pre-determined stage to receive' fluid under pressure from within the rings and hydraulic end thust balancing means having communication with said chamber.

2. In a centrifugal pump an outer casing,

a plurality of diffusion rings-within theouter casing and constructed to form an inner casing, said outer casing and diffusion rings having a chamber between their facing surfaces for receiving fluid under pressure, and hydraulic end thrust balancin means having communication with said 0 amber.

3. In a centrifugal pump, an outer casing, a plurality of diffusion rings within the outer casing and constructed to forin an inner casing, said diffusion rings and outer f casing arranged to form achamber between their facing surfaces, said chamber provided for receiving fluid under pressure, the last stage diffusion ring of the pump having a cone bearing thereon, and a bull ring engaging said cone bearing and the interior .of the outer casing. to form a seal and bind v the inner and outer casings substantially, in eflect,.1nto a s ngle casing.

-15. In a centrifugal pump, an outer casing,

aseries of diffusion rings within the outercasing and constructed to form an inner casing, said difiusion rings disposed in engage-' ment one with the one next thereto and constructed and providing exposed surfaces.

whereby the stage pressure in the pump rings will maintain the rings in tight engagement with each other, the last stage diffusion ring having a cone bearing thereon, and a bull ring engaging said cone bearing and the interior of the outer casing to form a seal and bind the inner and outer casings substantially, in efl'ect, into a single casing. I

5. In a centrifugal pump, an outer casing. an inner casing, said inner casing having a cone bearing thereon at the discharge end of the pump and a bull ring engaging said cone bearing and the interior of the outer casing to form a seal and bind the; inner and outer casings substantially, in effect, into a single casing. y

.6. A centrifugal pump including an outer casing and an inner casing and having a series of annular clearance spaces between said casings for receiving fluid under pressure, said outer casing provided with a channel establishing communication between said clearance spaces, and hydraulic end thrust balancing means having communication with said channel. I

7; A centrifugal pump having an outer casing, a plurality of diffusion rings within the outer casing, said diffusion rlngs and casing arranged to form a series of annular clearance spaces between the outer surfaces of fluid entering the pump being provided.

with openings to permit a part of the fluid entering the pump to pass into said chamber, and hydraulic end thrust balancing means having communication with said chamber.

9, In a centrifugal pump, a series of diffusion rings disposed in engagement one.

with the one next thereto and constructed :and providing exposed surfaces whereb the the rings in tight engagement with each.

other, and means establishing a pressure tightened fluid tight engagement between the discharge stage diffusion ring and the casing, said means forming the perimetric portion of the discharge stage of the pump.

10. In a centrifugal pump, a series of diffusion rings dis osed in engagement one with the one next t ereto and constructed and providing exposed surfaces whereby the stage pressures in the pump causing thrust pressure on the diffusion rings will maintain the rings in tight engagement with each other, and each ring will carry the thrust from the next succeeding rin", and members having inclined engaging surfaces carried by the last stage diffusion ring and casing for providing a pressure tightened connection etween the last stage difl'usion ring and casing, said members forming the perimetric portion of the discharge stage of the pump. 11. In a multi-stage centrifugal pump, an outer casing, a plurality of diffusion rings within the outer casing and each forming substantially one stage ofthe pump, a chamber between all the said rings and outer casing exce t the final rin at the discharge end of t e pump, said c amber adapted to receive fluid under pressure from a point where it is less .than it is at ,the pump discharge.

12.- In a multi-st-age centrifugal pump, an outer casing, a plurality of diffusion rings within the outer casing and each forming substantially one stage of the pump, a cham' ber between all the said rin and outer casing except the final ring at t e discharge end of the pump, said chamber adapted 'to receive fluid under pressure from a point where it is less than it is at the pump discharge, and a tapered pressure tightened thrust connection between the discharge stage forming ring and the casing. v a

13. In a multi-stage centrifugal pump, an outer casing, a plurality 'of difiusion rings within the outer casing and 1 each forming substantially one stage of the pump, a chamber between all the said rings and outer casing except the final ring at the discharge end of the pump, said chamber adapted to receive fluid under pressure from a point where 'it is less than it is at the pump discharge,

and hydraulic end thrust balancing means having communication with said' chamber.

, 14. In a multi-stage centrifugal pump, an outer casing, a plurality of diffusion rings within the casing and forming the stages of the pum ,said casing provided with a plu rality o spaced annular ribs, and annular ribs on said rings extending into the spaces between the casing carried ribs. a

15. Ina centrifugal pump, a series of diffusion rings disposed in engagement one with the one next thereto and constructed and providing exposed surfaces whereb the stage pressures in the pump causing thrust pressure on the diffusion rings will maintain the rings in tight enga ement with each other, and each ring wil carry the thrust from thenext succeeding ring, inclined engaging surfaces carried by the last stage difusion ring and casing for roviding a pressure tightened connection etween the last stage difiusion ring and casing, said casing provided with a plurality of annular ribs,

and spaced annular ribs on said rings ex-- tendin into the spaces between the casing carrie ribs. Y i

In testimony whereof we aflix our signatures.

MAX SPILLMANN. OSCAR DOBER: 

